Electronic equipment rack

ABSTRACT

A two-post electronic equipment rack of this invention is adapted for holding telecommunication equipment and the like. The rack comprises a structural frame including a base and a pair of posts secured to the base and extending up from the base adjacent opposite sides of the base. Each of the posts comprises substantially vertical front and back tubular frame members having a centerline spacing of less than about twelve in. The structural frame also includes a plurality of cross braces connecting the front and back tubular frame members of each of the two posts. A plurality of substantially vertical equipment mounting rails not constituting part of the structural frame are attached to the structural frame for mounting the equipment on the rack.

BACKGROUND OF THE INVENTION

This invention relates generally to electronic equipment racks, andparticularly to such racks that are adapted to withstand seismic events.

Racks for holding electronic equipment, such as telecommunicationsequipment, come in various configurations. Some racks, referred to as“two-post” racks, include a pair of upright posts, one at each side ofthe rack. Other racks, referred to as cabinets, include four uprightposts, two toward the front of the rack at opposite sides of the rackand two toward the back of the rack at opposite sides of the rack.Typical cabinets have side panels extending between the front and backposts at opposite sides of the cabinet. Conventional two-post rackstypically occupy less space but they are not as effective inwithstanding seismic events absent substantial (and expensive)reinforcement. Cabinets, on the other hand, are generally more durableduring seismic activity but consume large amounts of space, since thecenterline spacing between the front and back posts is typically greaterthan 18 in. (e.g., 24-48 in.). There is a need, therefore, for anelectronic equipment rack that is sufficiently strong to withstandseismic events yet relatively compact to conserve space.

SUMMARY OF THE INVENTION

Among the several objects of this invention may be noted the provisionof an improved two-post electronic equipment rack for holdingtelecommunications equipment and the like; the provision of such a rackwhich, in at least one embodiment, is designed to withstand seismicevents; the provision of such a rack which, in at least one embodiment,is relatively compact to preserve space; the provision of such a rackwhich, in at least one embodiment, is relatively lightweight (e.g.,about 100 lbs) yet capable of holding a relatively heavy load ofequipment (e.g., up to 1000 lbs); the provision of such a rack which, inat least one embodiment, is economical to manufacture; and the provisionof such a rack which, in at least one embodiment, permits cable to beconveniently routed to and from the equipment on the rack.

In general, a two-post electronic equipment rack of this inventioncomprises a structural frame including a base and a pair of postssecured to the base and extending up from the base adjacent oppositesides of the base. Each of the posts comprises substantially verticalfront and back tubular frame members having a centerline spacing of lessthan about twelve in. The structural frame further comprises a pluralityof cross braces connecting the front and back tubular frame members ofeach of the two posts. A plurality of substantially vertical equipmentmounting rails not constituting part of the structural frame areattached to the structural frame for mounting the equipment on the rack.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of one embodiment of a rack of this invention;

FIG. 2 is an enlarged view of the upper left-hand corner of the rack ofFIG. 1;

FIG. 3 is a perspective of an upper portion of the rack adapted to holda cable tray (shown in phantom lines);

FIG. 4 is a perspective of a lower portion of the rack;

FIG. 5 is an enlarged view of the lower left-hand corner of the rack ofFIG. 4;

FIG. 6 is a view similar to FIG. 5 with the components used to securethe rack to the floor exploded;

FIG. 7 is a front view of a top portion of the rack, a cable traysupported by the rack being shown in phantom;

FIG. 8 is a perspective of a lower portion of a second embodiment of arack having interior gussets; and

FIG. 9 is a front view of the rack;

FIG. 10 is an enlarged view of the upper left-hand corner of the rack ofFIG. 9 showing weld locations;

FIG. 11 is an enlarged view of the lower left-hand corner of the rack ofFIG. 9 showing weld locations;

FIG. 12 is a section taken along line 12-12 of FIG. 11 showing weldlocations;

FIG. 13 is a side view of the rack;

FIG. 14 is an enlarged view showing weld locations on a tab of FIG. 13;

FIG. 15 is an enlarged view showing weld location on a cross brace shownin FIG. 13; and

FIG. 16 is an enlarged view showing weld location on a front gusset andon a back gusset shown in FIG. 15.

Corresponding parts are designated by corresponding reference numbersthroughout the several views of the drawings.

DETAILED DESCRIPTION

Referring to FIG. 1 of the drawings, one embodiment of a two-postelectronic equipment rack of this invention is designated in itsentirety by the reference numeral 1. In general, the rack 1 comprises astructural frame, generally indicated at 3, and a plurality ofnon-structural substantially vertical equipment mounting rails, eachdesignated 5, attached to the structural frame for mounting electronicequipment 9 on the rack. The electronic equipment 9 illustrated in FIG.1 is telecommunications equipment (e.g., patch panels), but it will beunderstood that the rack 1 is suitable for mounting other types ofequipment as well.

The structural frame 3 includes a base, generally designated 11, and apair of left and right posts, each generally designated 15, secured tothe base and extending up from the base adjacent opposite sides of thebase. Each of the posts 15 comprises front and back substantiallyvertical tubular frame members 15F, 15B. As used herein, a frame member15F, 15B is “substantially vertical” if it is oriented at an angle of upto about twenty degrees off vertical, it being understood that it may bedesirable under some circumstances to angle one or both frame members15F, 15B relative to one another so they converge in an upwarddirection. The front and back tubular frame members 15F, 15B are said tocomprise a single “post” because the centerline spacing S between thetwo frame members is relatively close, i.e., less than about 12 in (FIG.2). By way of example, the centerline spacing S may be about 8 in.,although this dimension may vary. In the illustrated embodiments, thetubular frame members 15F, 15B are generally rectangular in crosssection, but other cross sections are possible (e.g., circular, square,triangular). Further, the tubular frame members 15F, 15B may be formedwith or without longitudinal seams. In general, the tubular framemembers 15F, 15B of a rack 1 of this invention are more effective thanopen structural shapes such as angle, channel or Z-shaped frame membersin resisting torsional and compressive forces, for example.

With particular reference to FIG. 3, the structural frame 3 alsoincludes a substantially horizontal front top frame member 17Fconnecting upper ends of the front tubular frame members 15F and asubstantially horizontal back top frame member 17B connecting upper endsof the back tubular frame members 15B. In one embodiment these framemembers 17F, 17B are angle bars each having a vertical leg 19 secured torespective front and back faces of the front and back tubular framemembers 15F, 15B, and a horizontal leg 21 with fastener openings 23 forsecuring additional structure to the frame 3 of the rack 1. Otherconfigurations are possible.

The structural frame 3 further comprises a plurality of cross braces 25connecting the front and back tubular frame members 15F, 15B of eachpost 15 (FIG. 1). In the illustrated embodiment, the tubular framemembers 15F, 15B of each post 15 are connected by four such cross braces25, a lower brace adjacent the base 11, an upper brace adjacent theupper ends of the frame members 15F, 15B, and two braces spaced atintervals between the upper and lower braces. It will be understood thatthe number of braces 25 may vary. Each brace 25 may be generallychannel-shaped, with a relatively wide central web 27 and narrow upperand lower flanges 29 extending from the web (FIG. 2). Otherconfigurations are possible. For enhanced stability, each cross brace 25desirably has a vertical dimension or height D1 greater than at leastabout 0.5 times the horizontal distance D2 between respective front andback tubular frame members 15F, 15B, more desirably greater than atleast about 0.75 times the horizontal distance D2, and even moredesirably greater than at least about 0.80 times the horizontal distanceD2. By way of example, where D2 is 12 in., D1 may be 9.6 in, and whereD2 is 4.0 in., D1 may be 3.2 in. The cross braces 25 have openings 31therein, e.g., horizontal rows of fastener holes, the function of whichwill become apparent.

Referring again to FIG. 3, the upper cross braces 25 at opposite sidesof the frame 3 are spaced below the upper ends of the front and backtubular frame members 15F, 15B for defining, in combination with thefront and back top frame members 17F, 17B, a channel space 33 sized toreceive cable or a cable tray 35 for holding cable extending across therack at a level at or below a top of the rack 1. By way of example, awire basket-type cable tray 35 is shown in phantom. Other types of cabletray may be used.

With reference to FIGS. 4-6, the base 11 comprises a front base framemember 37F connecting lower ends of the front tubular frame members 15F,and a back base frame member 37B connecting lower ends of the backtubular frame members 15B. In the illustrated embodiment, each of thesebase frame members 37F, 37B comprises a substantially vertical upper leg39 having opposite ends which overlap and are secured to respectivetubular frame members 15F, 15B, as by welding, and a substantiallyhorizontal lower leg 41 extending from the lower edge of the upper legin a direction away from the center of the rack 1. A horizontal flange43 extends from the upper edge of the vertical leg 39 in a directionopposite the lower leg 41, i.e., toward the center of the rack. Thehorizontal flanges 43 have lengths generally corresponding to theside-to-side spacing between the tubular frame members 15F, 15B, so thatthe ends of the flanges are closely adjacent respective tubular members.In one embodiment, each base frame member 37F, 37B is formed from asingle piece of sheet metal bent into the desired shape, but the framemember may be fabricated from multiple pieces. Other shapes are possibleas well. The area between the vertical legs 39 of the front and backbase frame members 37F, 37B is substantially open (i.e., the rack has nobottom or a largely open bottom between the front and back base framemembers) so that cable may be routed to and from the equipment 9 throughthis open area at the lower end of the rack 1. Holes 45 are alsoprovided in one or both of the vertical legs 39 of the base framemembers 37F, 37B for installation of electrical devices (e.g., outlets).

The base 11 also includes a pair of side gussets 47 at opposite sides ofthe rack connecting respective front and back tubular frame members 15F,15B. In one embodiment, the side gussets 47 have quadrilateral uprightplate portions 49 attached (e.g., welded) to respective front and backtubular frame members 15F, 15B and rectangular lower plate portions 51underlying the lower legs 41 of the front and back base frame members37F, 37B. Horizontal flanges 53 are provided along the upper edges ofthe upright plate portions 49 of the gussets 47. As best illustrated inFIGS. 5 and 6, these flanges 53 have lengths generally corresponding tothe spacing between the front and back tubular frame members 15F, 15Band depths (widths) such that the flanges terminate at or close to thewebs 27 of respective lower cross braces 25. Holes 55 are provided inthe upright plate portions 49 of the gussets 47 for routing cable to andfrom the equipment 9 on the rack 1.

The base 11 also includes washers 58 and reinforcing slabs 57 (e.g., 0.5in. thick metal slabs) overlying the lower legs 41 of respective baseframe members 37F, 37B and the lower plate portions 51 of respectiveside gussets 47 (see FIG. 6). These washers 58, slabs 57, the lower legs41 of the base frame members 37F, 37B and the lower plate portions 51 ofthe side gussets 47 have vertically aligned openings 59 therein forreceiving fasteners 61 (e.g., bolts) for securing the rack 1 to a floor.The openings 59 in the washers are circular whereas the openings in theslabs 57, the lower legs 41 of the base frame members 37F, 37B and thelower plate portions 51 of the side gussets 47 are oblong. As a result,the bolts 61 and washers 58 are positionable at any location along thelength of the oblong openings 59. Desirably, the distance between thecenter of one set of vertically aligned openings 59 and a respectiveadjacent tubular frame member 15F, 15B is relatively small (e.g., about2 in.). By reducing the distance from the tubular frame members 15F, 15Bto the bolts 61, less material thickness is required in the areas of thebase between the bolts and respective frame members to withstand theforces exerted during a seismic event.

With reference to FIGS. 1 and 7, the mounting rails 5 for mounting theequipment 9 on the rack 1 are preferably movable independent of theframe 3 so that during a seismic event the rails are adapted to move(flex) at a harmonic frequency different from the harmonic frequency ofthe structural frame. This difference serves as a vibration dampingsystem tending to reduce the overall amplitude and/or frequency ofvibration of the rack during seismic activity, which decreases the riskof damage to and/or failure of the rack 1. Preferably, the configurationof the rack 1 should be such that the structural framework carrying amaximum equipment load has a natural harmonic frequency greater than thehigh-amplitude frequencies of a typical seismic event (e.g., about 15 Hzcompared to less than 10 Hz). Also preferably, the equipment mountingrails 5 should have natural harmonic frequency different from (greateror less than) that of the structural framework of the rack 1 and greaterthan the high-amplitude frequencies of a seismic event. By way ofexample, the mounting rails 5 may have a natural harmonic frequency ofabout 12 Hz.

In one embodiment, the equipment mounting rails 5 comprise angle bars,each having a first vertical leg 63 extending in a side-to-side plane ofthe rack 1 and a second vertical leg 65 extending in a front-to-backplane of the rack (see FIG. 8). The first (side-to-side) legs 63 of therails 5 have fastener openings 67 spaced at regular intervals alongtheir lengths for attachment of electronic equipment 9 to the rails. Byway of example, the openings 67 may be circular holes spaced at regularintervals (e.g., a series of holes which repeat at ⅝ in. −⅝ in. −½ in.intervals), or at intervals corresponding to a standard rack-mountingunit (RMU). The second (front-to-back) legs 65 of the rails 5 havefastener openings 69 spaced along their lengths which are adapted toalign with selected openings 31 in the cross braces 25 for securement ofthe rails to the cross braces at desired positions by suitable fasteners71 (FIG. 2). The positions of the equipment mounting rails 5 can beadjusted as needed simply by removing the fasteners 71, relocating therails, and then refastening the rails to the cross braces 25.

Referring to FIGS. 1 and 14, tabs 72 are affixed to the front and backtubular frame members 15F, 15B at opposite sides of the rack 1. Thesetabs 72 are formed with apertures 74 which are vertically aligned withother apertures 74A in respective side gussets 47 of the rack forreceiving fasteners to secure one or more wire management devices to therack. The rack 1 may have any number of tabs 72 or other mountingelements. Alternatively, the tabs 72 may be eliminated altogether.

Optionally (FIG. 8), the base 11 further comprises a plurality ofinterior gussets 73 above the lower legs 41 of the base frame members37F, 37B, each interior gusset 73 having a triangular upright portion 75attached (e.g., welded) to a vertical leg 39 of a respective front orback base frame member 37F, 37B and a quadrilateral lower portion 77overlying the lower leg of a respective base frame member. The lowerportions 77 of the interior gussets 73 are sandwiched between the lowerlegs 41 of respective base frame members 37F, 37B and respectivereinforcing slabs 57, and they are also positioned directly over thelower portions 51 of the side gussets 47, creating a type of “stirrup”arrangement for added strength. The lower portions 77 of the interiorgussets 73 have oblong openings (not shown) therein vertically alignedwith respective openings 59 in the slabs 57, in the washer 58, in thelower legs 41 of respective base frame member 37F, 37B, and inrespective lower plate portions 51 of the side gussets 47 for receivingthe aforesaid fasteners 61. The interior gussets 73 strengthen the rack1 and are useful in situations where the rack is intended to carry moreweight than the previous embodiment, e.g., 1000 lbs of equipmentcompared to 750 lbs.

The various components of the rack 1 may be secured together in suitablefashion. For example, certain components can be welded together as shownin FIGS. 9-16, the weld lines being indicated by xxxxx on FIGS. 10-12and 14-16. The structural components of the rack frame 3 (e.g., framemembers and base components) are preferably fabricated from relativelylight gauge structural steel, e.g., metal tubing having a wall thicknessof 0.075 in., and metal plate having a thickness of 0.135 in. for thebase frame members 37F, 37B, gussets 47, 73 and top frame members 17F,17B, and a thickness of 0.075 in. for the cross braces 25. As a result,the rack 1 is relatively lightweight (e.g., 100 lbs or less) even thoughvery strong. The non-structural components of the rack 1 (e.g., themounting rails 5) may be fabricated from angle bar stock having athickness of 0.135 in. These thicknesses are illustrative only.

The rack 1 described above is strong and capable of withstanding seismicactivity. Further, the rack 1 is compact and is open at its front, back,top, bottom and sides to permit routing of cable to and from theequipment 9 on the rack in virtually any direction. The rack 1 is alsodesigned for convenient, compact installation of cable tray 35 adjacentthe top of the rack.

Certain of the features described above (e.g., the channel space 33 inthe top of the rack 1 for receiving cable tray 35) can be incorporatedin non-seismic racks without departing from the scope of this invention.

When introducing elements of the present invention or the preferredembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

1. A two-post electronic equipment rack, comprising a structural frameincluding a base and a pair of posts secured to the base and extendingup from the base adjacent opposite sides of the base, each of said postscomprising substantially vertical front and back tubular frame membershaving a centerline spacing of less than about twelve in., saidstructural frame further comprising a plurality of cross bracesconnecting the front and back tubular frame members of each of saidposts, and a plurality of non-structural substantially verticalequipment mounting rails attached to said structural frame for mountingsaid equipment on the rack.
 2. A rack as set forth in claim 1 whereinsaid mounting rails are movable independent of the frame whereby duringa seismic event the mounting rails are adapted to move at a harmonicfrequency different from the harmonic frequency of said structuralframe.
 3. A rack as set forth in claim 1 wherein said structural framealso includes a substantially horizontal front top frame memberconnecting upper ends of the front tubular frame members and asubstantially horizontal back top frame member connecting upper ends ofthe back tubular frame members, and wherein said plurality of crossbraces include a pair of upper cross braces at opposite sides of theframe spaced below the upper ends of the front and back tubular membersfor defining, in combination with said front and back top frame members,a space sized and configured to receive cable or a cable tray forholding cable extending across the rack at a level at or below a top ofthe rack.
 4. A rack as set forth in claim 1 wherein the rack has opensides, an open front and an open back to permit routing of cable to andfrom said equipment through said open sides, said open front and saidopen back.
 5. A rack as set forth in claim 4 wherein the rack has anopen top and an open bottom to permit routing of cable to and from saidequipment through said open top and bottom.
 6. A rack as set forth inclaim 1 wherein said base comprises a front base frame member connectinglower ends of the front tubular frame members, a back base frame memberconnecting lower ends of the back tubular frame members, and a pair ofside gussets connecting respective front and back tubular frame members,said side gussets having upright plate portions attached to respectivefront and back tubular frame members and lower plate portions underlyingrespective front and back base frame members.
 7. A rack as set forth inclaim 6 further comprising reinforcing slabs overlying respective baseframe members and respective lower plate portions of the side gussets,said slabs, base frame members and respective lower plate portions ofthe side gussets having vertically aligned openings therein forreceiving fasteners for securing the rack to a floor.
 8. A rack as setforth in claim 7 wherein the distance between a center of one set ofsaid vertically aligned openings and a respective tubular frame memberis about 2 in.
 9. A rack as set forth in claim 7 wherein said basefurther comprises a plurality of interior gussets above respective baseframe members, each interior gusset having an upright portion attachedto a vertical leg of a respective front or back base frame member and alower portion overlying a lower leg of a respective front or back baseframe member.
 10. A rack as set forth in claim 9 wherein the lowerportions of said interior gussets are sandwiched between the lower legsof respective base frame members and respective reinforcing slabs, andwherein said lower portions of said interior gussets have openingstherein vertically aligned with openings in respective slabs, respectivelower legs of the base frame members, and lower plate portions ofrespective side gussets for receiving said fasteners.
 11. A rack as setforth in claim 1 wherein said cross braces have a vertical dimensiongreater than at least about 0.5 times the horizontal distance betweenrespective front and back tubular frame members.
 12. A rack as set forthin claim 1 wherein said tubular frame members are generally rectangularin cross section, and wherein said mounting rails comprise verticalangle bars secured to said cross braces.